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Lactobacillus is a genus of Gram-positive, facultative anaerobic or microaerophilic, rod-shaped, non-spore-forming bacteria. They are a major part of the lactic acid bacteria group. In humans, they constitute a significant component of the microbiota at a number of body sites. In women, Lactobacillus species are normally a part of the vaginal microbiota.
Biology and biochemistry
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Lactobacillus is group of rod-shaped, Gram-positive (it retains crystal violet dye), non-spore-forming, facultative anaerobe (it can produce energy through glycolysis and fermentation when oxygen is not present) bacteria. Lactobacillus is a member of the lactic acid bacteria group (its members convert lactose and other sugars to lactic acid).
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Many Lactobacilli operate using homofermentative metabolism (they produce only lactic acid from sugars), and some species of Lactobacilli use heterofermentative metabolism (they can produce either alcohol or lactic acid from sugars). They are aerotolerant despite the complete absence of a respiratory chain. This aerotolerance is manganese-dependent and has been explored (and explained) in Lactobacillus plantarum. Many species of this genus do not require iron for growth and have an extremely high hydrogen peroxide tolerance.
Many species in this genus have had their genomes sequenced.Lactobacillus consists of a wealth of compound microsatellites in the coding region of the genome, which are imperfect and have variant motifs.
The genus Lactobacillus currently contains over 180 species and encompasses a wide variety of organisms. The genus is polyphyletic, with the genus Pediococcus dividing the L. casei group, and the species L. acidophilus, L. salivarius, and L. reuteri being representatives of three distinct subclades. The genus Paralactobacillus falls within the L. salivarius group. In recent years, other members of the genus Lactobacillus (formerly known as the Leuconostoc branch of Lactobacillus) have been reclassified into the genera Atopobium, Carnobacterium, Weissella, Oenococcus, and Leuconostoc. More recently, the Pediococcus species P. dextrinicus has been reclassified as a Lactobacillus species. According to metabolism, Lactobacillus species can be divided into three groups:
- Obligately homofermentative (group I) including:
- Facultatively heterofermentative (group II) including:
- Obligately heterofermentative (group III) including:
Lactobacillus species produce hydrogen peroxide which inhibits the growth and virulence of the fungal pathogen Candida albicans in vitro and in vivo. Following antibiotic therapy, certain Candida species can suppress the regrowth of Lactobacillus species at body sites where they cohabitate, such as in the gastrointestinal tract.
Lactobacillus species administered as a single probiotic agent is of no benefit in people with irritable bowel syndrome or Crohn's disease. When it is administered in combination with other probiotics, may help people with irritable bowel syndrome, although in a minority of cases may cause negative side effects, uncertainty remains around which type of probiotic works best, and around the size of the effect. Lactobacillus and bifidobacteria probiotics can reduce clinical symptoms of pouchitis and cholangitis. L. acidophilus is used to prevent necrotizing entercolitis and other neonatal infections.
Some Lactobacillus species have been associated with cases of dental caries. Lactic acid can corrode teeth, and the Lactobacillus count in saliva has been used as a "caries test" for many years. Lactobacilli characteristically cause existing carious lesions to progress, especially those in coronal caries. The issue is, however, complex, as recent studies show probiotics can allow beneficial lactobacilli to populate sites on teeth, preventing streptococcal pathogens from taking hold and inducing dental decay. The scientific research of lactobacilli in relation to oral health is a new field and only a few studies and results have been published.
Some Lactobacillus species are used as starter cultures in industry for controlled fermentation in the production of yogurt, cheese, sauerkraut, pickles, beer, cider, kimchi, cocoa, kefir, and other fermented foods, as well as animal feeds. The antibacterial and antifungal activity of Lactobacillus species rely on production of bacteriocins and low molecular weight compounds that inhibits these microorganisms.
Sourdough bread is made either spontaneously, by taking advantage of the bacteria naturally present in the air, or by using a "starter culture", which is a symbiotic culture of yeast and lactic acid bacteria growing in a water and flour medium. The bacteria metabolize sugars into lactic acid, which lowers the pH of their environment, creating a signature "sourness" associated with yogurt, sauerkraut, etc.
In many traditional pickling processes, vegetables are submerged in brine, and salt-tolerant Lactobacillus species feed on natural sugars found in the vegetables. The resulting mix of salt and lactic acid is a hostile environment for other microbes, such as fungi, and the vegetables are thus preserved—remaining edible for long periods.
Lactobacilli, especially L. casei and L. brevis, are some of the most common beer spoilage organisms. They are, however, essential to the production of sour beers such as Belgian lambics and American wild ales, giving the beer a distinct tart flavor.
- Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; et al. (Oct 2006). "Comparative genomics of the lactic acid bacteria". Proc Natl Acad Sci U S A. 103 (42): 15611–6. doi:10.1073/pnas.0607117103. PMC . PMID 17030793.
- Petrova, Mariya I.; Lievens, Elke; Malik, Shweta; Imholz, Nicole; Lebeer, Sarah (2015). "Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health". Frontiers in Physiology. 6. doi:10.3389/fphys.2015.00081. ISSN 1664-042X.
- Fijan, Sabina (2014). "Microorganisms with Claimed Probiotic Properties: An Overview of Recent Literature". International Journal of Environmental Research and Public Health. 11 (5): 4745–4767. doi:10.3390/ijerph110504745. ISSN 1660-4601.
- Basharat, Z; Yasmin, A (2015). "Survey of compound microsatellites in multiple Lactobacillus genomes". Canadian Journal of Microbiology. 61 (12): 898–902. doi:10.1139/cjm-2015-0136. ISSN 0008-4166.
- (IJSEM, Paper in Press).
- Wang ZK, Yang YS, Stefka AT, Sun G, Peng LH (April 2014). "Review article: fungal microbiota and digestive diseases". Aliment. Pharmacol. Ther. 39 (8): 751–766. doi:10.1111/apt.12665. PMID 24612332.
In addition, GI fungal infection is reported even among those patients with normal immune status. Digestive system-related fungal infections may be induced by both commensal opportunistic fungi and exogenous pathogenic fungi. ...
In vitro, bacterial hydrogen peroxide or organic acids can inhibit C. albicans growth and virulence61
In vivo, Lactobacillus sp. can inhibit the GI colonisation and infection of C. albicans62
In vivo, C. albicans can suppress Lactobacillus sp. regeneration in the GI tract after antibiotic therapy63, 64
- Erdogan A, Rao SS (April 2015). "Small intestinal fungal overgrowth". Curr Gastroenterol Rep. 17 (4): 16. doi:10.1007/s11894-015-0436-2. PMID 25786900.
Small intestinal fungal overgrowth (SIFO) is characterized by the presence of excessive number of fungal organisms in the small intestine associated with gastrointestinal (GI) symptoms. Candidiasis is known to cause GI symptoms particularly in immunocompromised patients or those receiving steroids or antibiotics. However, only recently, there is emerging literature that an overgrowth of fungus in the small intestine of non-immunocompromised subjects may cause unexplained GI symptoms. ... Fungal-bacterial interaction may act in different ways and may either be synergistic or antagonistic or symbiotic . Some bacteria such as Lactobacillus species can interact and inhibit both the virulence and growth of Candida species in the gut by producing hydrogen peroxide . Any damage to the mucosal barrier or disruption of GI microbiota with chemotherapy or antibiotic use, inflammatory processes, activation of immune molecules and disruption of epithelial repair may all cause fungal overgrowth .
- Ford, Alexander C; Quigley, Eamonn M M; Lacy, Brian E; Lembo, Anthony J; Saito, Yuri A; Schiller, Lawrence R; Soffer, Edy E; Spiegel, Brennan M R; Moayyedi, Paul (2014). "Efficacy of Prebiotics, Probiotics, and Synbiotics in Irritable Bowel Syndrome and Chronic Idiopathic Constipation: Systematic Review and Meta-analysis". The American Journal of Gastroenterology. 109 (10): 1547–1561. doi:10.1038/ajg.2014.202. ISSN 0002-9270.
- Ghouri YA, Richards DM, Rahimi EF, Krill JT, Jelinek KA, DuPont AW (Dec 9, 2014). "Systematic review of randomized controlled trials of probiotics, prebiotics, and synbiotics in inflammatory bowel disease". Clin Exp Gastroenterol (Review). 7: 473–87. doi:10.2147/CEG.S27530. PMC . PMID 25525379.
- Saez-Lara, Maria Jose; Gomez-Llorente, Carolina; Plaza-Diaz, Julio; Gil, Angel (2015). "The Role of Probiotic Lactic Acid Bacteria and Bifidobacteria in the Prevention and Treatment of Inflammatory Bowel Disease and Other Related Diseases: A Systematic Review of Randomized Human Clinical Trials". BioMed Research International. 2015: 1–15. doi:10.1155/2015/505878. ISSN 2314-6133.
- Baucells, B.J.; Mercadal Hally, M.; Álvarez Sánchez, A.T.; Figueras Aloy, J. (2015). "Asociaciones de probióticos para la prevención de la enterocolitis necrosante y la reducción de la sepsis tardía y la mortalidad neonatal en recién nacidos pretérmino de menos de 1.500g: una revisión sistemática". Anales de Pediatría. doi:10.1016/j.anpedi.2015.07.038. ISSN 1695-4033.
- Twetman, S; Stecksén-Blicks, C (2008). "Probiotics and oral health effects in children". International Journal of Paediatric Dentistry. 18 (1): 3–10. doi:10.1111/j.1365-263X.2007.00885.x. PMID 18086020.
- Meurman, J. H.; Stamatova, I (2007). "Probiotics: Contributions to oral health". Oral Diseases. 13 (5): 443–51. doi:10.1111/j.1601-0825.2007.01386.x. PMID 17714346.
- Bravo, J. A.; Forsythe, P.; Chew, M. V.; Escaravage, E.; Savignac, H. M.; Dinan, T. G.; Bienenstock, J.; Cryan, J. F. (2011). "Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve". Proceedings of the National Academy of Sciences. 108 (38): 16050–16055. doi:10.1073/pnas.1102999108. ISSN 0027-8424.
- Wang, Yan; Kasper, Lloyd H. (2014). "The role of microbiome in central nervous system disorders". Brain, Behavior, and Immunity. 38: 1–12. doi:10.1016/j.bbi.2013.12.015. ISSN 0889-1591.
- Inglin, Raffael C. (2015). "High-throughput screening assays for antibacterial and antifungal activities of Lactobacillus species". Journal of Microbiological Methods. 114 (July 2015): 26–29. doi:10.1016/j.mimet.2015.04.011.